The present invention relates generally to railway safety and property protection and more particularly relates to an apparatus for detecting a hazardous failure of the running gear of a railway freight or passenger car, locomotive unit or the associated rails and then immediately and automatically initiating the emergency state of the railway train.
Severe catastrophic railroad train wrecks are usually preceded by a mechanical failure which does not immediately result in a catastrophic crash. Ordinarily a substantial time period elapses after the failure and before the major wreck. Consequently, there is a need for an apparatus which can detect such failures immediately upon their occurrence and automatically apply the train brakes in an emergency state to stop the train before a catastrophic wreck occurs.
For example, it is not unusual for two or four wheels of one truck of a railway car to be removed from their usual engagement with the tracks and yet be dragged unnoticed along the tracks for a considerable distance. While such a derailment may continue for several miles, it ordinarily produces only minor damage. However, it can result in a catastrophic wreck if the derailed truck strikes a highway crossing, switching gear or the like which can catch the derailed wheels and cause one or more cars to entirely leave the track.
The relatively minor derailment described above ordinarily goes unnoticed by the train and engine crew unless they are signalled by a yard man or another person who observes the derailed wheels being dragged along the track. There is therefore a need for an apparatus which will detect such a minor derailment and immediately put the train into emergency stop.
Similarly, there are other mechanical failures which do not immediately cause catastrophic damage but which, if left undetected, can eventually produce severe damage and eventually catastrophic derailment. For example, occasionally the center pin of the railway truck sheers off permitting the truck to slide off center. In other instances a part of the brake rigging which is mounted to the truck for actuating the brake shoes has been broken and dropped toward the road bed.
There is therefore a need for a single apparatus which can detect all of the aforementioned mechanical failures and immediately and automatically throw the train into an emergency state without requiring the intervention of the engineer.
Prior workers in the art have disclosed systems for causing the breakage of an air conducting tube, which is connected to the air brake system of the car, upon a railway car derailment. While most of these prior art systems will respond to at least one hazardous condition, the prior art devices exhibit two types of weaknesses. Firstly, they do not respond to all the hazardous failure conditions which are described above and secondly, many are falsely actuated by nonhazardous conditions normally encountered by a railway car.
For example, some of the prior art devices are mounted to the body of the railway car and therefore may be actuated and switch the train into an emergency state as a result of a normal, lateral, rocking motion of the railway car. Still others are mounted to extend to a position immediately above a track and consequently when the wheels of the train become derailed and offset from the track, the prior art device is similarly misaligned and is not actuated.
Still other prior art devices are mounted on the lateral, exterior sides of the wheels making them attractively available for unwanted tampering or vandalism by persons along the track. This accessibility similarly makes them more likely to be struck by obstructions along the sides of the track. Other prior art devices require the mounting of one detector for each wheel of the car therefore requiring excessive cost and labor.
Still other prior art devices depend upon mechanical linkages for actuating valves and consequently are of reduced reliability after having been exposed to the corrosive environment of railway vehicles.